Abstract

The bending of a liquid interface by the radiation pressure of a cw laser
wave is generally weak. To strongly enhance the coupling, we investigate lensing
in a near-critical phase-separated liquid mixture. By continuously tuning
the softness of the meniscus by varying the temperature, we observed huge
stationary interface deformations at low beam power that led to an important
variation of the resultant soft lensing. We also illustrate the crucial role
played by temperature in this process to demonstrate its potential use in
lens adaptation.

Figures (4)

Optical deformation of the meniscus of
a phase-separated liquid mixture induced by radiation pressure. The cw laser
beam is represented by the arrows. ϱ1 and n1 (ϱ2 and n2) are the density and the refractive index of the lower (upper)
coexisting Phase Φ1Φ2. g→ represents the gravity field.

Variation of focal length induced by optical
bending versus beam intensity. The dashed curve is the fit from Eq. (4). Inset, log–log plot
of the same data; the measured slope is -1.15 instead of -1. The control parameters are T-TC=1.5K and values of ω0 (in micrometers of) 14.6Δ, 18.3(▲), 21.2□,25.3■,29.3○, and 32.1μm●.